Filters have been used in aquariums for many years to remove particulate matter from the aquarium water in order to keep the aquarium clean. Traditionally, the most common type of aquarium filter is a power filter which hangs on the outside of the aquarium over the top edge. It includes a siphon tube which carries water from the aquarium into a filter box. Water entering the filter box flows over various types of filter media to remove particulate matter from the water. The water passes through filter carbon to remove chemical impurities from the water which is then pumped back into the aquarium using a pump. Examples of such power filters include the Supreme Aqua King power filter marketed by E. G. Danner Manufacturing Co., the Second Nature Whisper power filter marketed by Willinger Bros. Mfg. Co., and the Aqua Clear power filter marketed by Rolf Hagen Manufacturing Co.
Another type of aquarium filter is a canister type filter which may be positioned outside and below the aquarium. Intake and output hoses hang over the aquarium edge and are connected to the canister filter on the floor. Water is fed by gravity through the intake hose from the aquarium to the canister. The aquarium water is both mechanically and chemically treated and pumped back into the aquarium by a pump contained in the canister. Examples of canister type filters include the Hagen Fluval filter marketed by Hagen USA Mfg., Co., Marine Land Canister Filter marketed by Aquaria, Inc., and Eheim Classic Canister Filters, marketed by Eheim GmbH & Co. KG.
An internally mounted power filter is still another type of aquarium filter. Such a filter comprises a small canister with a built-in pump which is submerged inside the aquarium. Water enters the bottom of the canister and flows through a filter sleeve which removes particulate and chemical waste. The filtered water is then pumped out the top of the canister and back into the aquarium. Examples of this type of filter are the Supreme Ovation internal filter marketed by Danner Mfg. and the Hagen Fluval internal filter sold by Hagen USA Mfg. Co.
Still another type of filter employed in aquariums is the undergravel filter which consists of a perforated raised plate which rests on the aquarium floor. Riser tubes are provided on either end of the filter and extend into the top of the aquarium. Gravel is placed on top of the plate to a thickness of about 2 inches. Air lines from an external pump are placed in the riser tubes to the bottom plate and an air stone is placed at the end of the air lines. Air is forced by the pump through the air stones thereby forcing air bubbles to travel up through the tubes to the water surface creating turbulence or current. Water is then pulled through the gravel and forced up the riser tubes. Waste from the aquarium is drawn through the gravel bed where bacteria break down any ammonia or nitrites to less harmful nitrates. A biological filter does not, however, remove all chemical wastes. Examples of such undergravel filters include filters marketed by Perfecto Mfg. and Penplex Mfg.
Yet another type of prior art filter commonly used in aquariums is a wet/dry trickle type filter which includes a skimmer box that hangs inside the aquarium at the top. Siphon tubes are provided for carrying water from the aquarium to a prefilter which is mounted directly behind the skimmer box on the outside of the aquarium. Water passes through foam sleeves in a pre-filter to trap particulate matter. The water then travels through the hose in a tank typically positioned beneath the aquarium. As water enters the tank beneath the aquarium, it flows onto a drip plate or spray bar in a dry chamber of filters which contains a plurality of plastic biospheres. Water drips over and through the biospheres to the bottom section of the tank. Bacteria colonies grow on all biospheres which feed on waste products in the water passing over them. From there, the water gathers in the bottom of the filter tank and then passes through a carbon filter or other filter to remove chemical wastes from the water. The water is then passed through dolomite, crushed coral or crushed clam shells to buffer the water which is then pumped through the return hose back to the aquarium. Wet/dry filters can include mechanical, chemical and biological filters. Examples of such filters are the Plus Series trickle filter marketed by Oceanic System, Inc. and the Perfecto Wet/Dry filtration system sold by Perfecto Mfg. Co.
Wet/dry filters may also be built into the aquarium and form a permanent part of the tank. One such wet/dry filter that is permanently built into the tank is marketed by Tenecor Corporation of Tempe, Ariz.
An alternative form of the wet/dry filter is an internally mounted wet/dry filter which includes an integrated pump and heater for small aquariums. The filter is placed inside the aquarium against the rear wall with the top of the filter at the water level. Water enters the filter and then passes through the filter cartridge which removes particulate and chemical waste materials. A portion of the water is then pumped into a drip plate in a dry chamber for biological filtration. The remaining water is then pumped directly back into the aquarium so as to bypass the dry area. One such filter is marketed by Rolf Hagen Mfg. under the trademark “Biolife” filter.
As should be clear from the above, proper and continuous filtration is critical to keeping happy, healthy fish, and there are three basic filtration methods: mechanical, biological and chemical. However, one long-standing problem is, e.g., that while freshly charged filter media accomplish their intended goals, over time, they tend to loose efficiency.
For example, mechanical filtration media, the means by which large particles of excess food and other debris are removed, screened, or skimmed from the water, may become clogged over time, reducing their ability to function as intended. Chemical filtration uses activated carbon and ammonia absorbents, such as zeolite, to remove odor, colors and harmful substances, such as ammonia, from the water. However, activated carbon will also loose its effectiveness over time and will similarly need replacement.
In addition, while replacement of mechanical and chemical filtration is ultimately necessary, careful attention must be placed upon the primary means of removing ammonia and nitrites (by-products of fish waste), which is the biological filter. A well-established aquarium is a natural ecosystem in which fish and the beneficial bacteria that naturally occur in an aquarium depend upon each other to live happily and healthy. The result of this interrelationship is commonly referred to as the “Nitrogen Cycle”. Fish eat and produce ammonia as a waste product. Excess food and plant materials also decay and produce ammonia. Beneficial bacteria (aerobic) neutralize the ammonia and produce nitrites, which in turn are neutralized by other beneficial bacteria that produce nitrates. Nitrates in normal levels are harmless to freshwater fish, and over time, can be readily removed from the aquarium by partial water changes. Thus, the natural system in an aquarium converts toxic ammonia into harmless nitrates; all without chemicals or consumer assistance.
Expanding upon the above, there clearly needs to be a place for the aerobic bacteria to foster and grow within the filter system. It turns out that bacteria will grow on any porous surface in the filter assembly, e.g., on the media in a canister filter that pumps a steady flow of water for the bacteria to survive. That is, the water must be oxygenated as the aerobic bacteria require oxygen to reproduce and grow. An aquarium with proper aeration of the water and good water flow over the beneficial bacteria will provide sufficient oxygen to maintain the beneficial aerobic bacteria. And, of course, there must be a source of food (ammonia) for the bacteria. Any tank with fish or plants will provide sufficient food. The filtration system then circulates the ammonia carrying water over the beneficial bacteria for them to eat.
Once established, the bacteria inside the canister filter assembly are clearly invaluable and critical for a successful aquarium. However, as noted, the need to remove and regularly exchange portions of the chemical and mechanical media is also necessary. However, when exchanging mechanical and chemical media, it is important to do so in a manner that would not totally disrupt the biological filter media, which could lead to catastrophic results.
That being the case, aquarium filtration technology has not yet developed a modular filter system that would allow the hobbyist a convenient way to exchange filter media in a rapid fashion such that any disruption of water flow is of little consequence. More specifically, aquarium filtration technology has not yet provided a cartridge filter assembly comprising one or a plurality of cartridges that could each be conveniently removed and exchanged for new media with minimal impact on the biological filter bed and without the hobbyist getting wet in the process.
That being the case, there is a need for an aquarium filter which includes a series of cartridges that are easy to access and change such that water flow is suspended for only a short time.
In addition, it is important that such filters are efficient and preferably provide a tortuous flow path along with sufficient residence time for the media to act upon the water.
U.S. Pat. No. 5,866,018, entitled “Vortex Aquarium Filter”, assigned to The Hartz Mountain Corporation is directed at an aquarium filter which can remove particles from aquarium water without the need for physical entrapment elements, comprising a first chamber having an annular wall and top and bottom, an inlet near the top of the first chamber positioned to create a vortex, an overflow outlet and a waste outlet. This reference appears to be directed at the removal of particulates by creating a vortex and illustrates in FIG. 1 chemical and biological filters which are separated from the claimed device. U.S. Pat. No. 5,830,360, entitled “Pour Though And Pitcher Mounted Water Filter For Removal Of Parasite Cysts, Bacteria And Viruses, And Method Of Filtering Water”, is directed at a gravity fed, pour-through water filtration device including a chamber housing a spiral filter.
U.S. Pat. No. 5,643,470, entitled “Centrifugal Flow Separator” is directed at a method for separating the constituents of a fluid comprising impeding the flow of the fluid to cause the fluid to move in a curvilinear path. A housing comprises an interior and an exterior chamber separated by a conical baffle which decreases in volume from a first end to a second end. Flow enters the exterior chamber and is impeded by striking the conical baffle, causing the fluid to move in a curvilinear path such that the fluid is affected by centrifugal forces which enhance the separation of the fluid ingredients. Subsequently, the fluid moves to a portion of the exterior chamber having increased volume to further enhance separation.
U.S. Pat. No. 5,030,349, entitled “Filter Apparatus” is directed at a fluid filter having a filter element including at least one group of disk-like elements, including at least an element of relatively fine porous material, having disposed on both sides thereof disk-like elements of a relatively coarse porous material each of the at least one group having disposed on both sides thereof a grooved spacer element.
U.S. Pat. No. 4,978,450, entitled “Filtering Element” is directed at a stack of discs comprising a plurality of co-operating filter elements having a first surface defining spaced circumferentially extending raised line portions separated by grooves and a second surface defining a plurality of radially extending fingers which communicate with the upstream and downstream sides of the stack.
U.S. Pat. No. 4,597,871, entitled “Apparatus For Removing Foreign Matters”, to Hitachi Ltd., is directed at a cylindrical housing, a radial inlet pipe mounted on an upper portion of the housing and an axial outlet pipe mounted on the lower portion of the housing. A conical filter is disposed therebetween. A deflector is mounted at the outlet of the inlet pipe to deflect the liquid so as to swirl it around the filter. Foreign matter is deposited on the filter, and condensed by centrifugal force and downward movement of the liquid.
U.S. Pat. No. 4,267,042, entitled “Water Filter, In Particular For Aquarium Water”, is directed at a filter chamber having an inlet and outlet and filled with exchangeable filter material. The filter chamber is defined by an annular space between two concentric tubes of different diameters. The outer tube of the filter cartridge may be formed as a corrugated tube with helical corrugations. This produces a flow pattern so that the water to be purified flows to those filter regions in which the filter material is least clogged. Both inner and outer tubes are perforated and the outer tube is encased by a shell of water permeable foam.
As can be seen, there exists a need for an aquarium filter which provides a series of canisters which may be easily attached together for biological, chemical and mechanical filtering, which provides efficient filtration and which may be exchanged in a short time period so as not to upset the balance in the aquarium.
Accordingly, it is an object of this invention to provide a filter system that can be mounted to or near the aquarium that has one or more particulate, biological and/or chemical filter cartridges that can easily be replaced. It is also an object of the invention to provide a filter system that allows the user to rapidly replace any of the filter cartridges with minimal disruption of flow, without repriming the system when completed, and without getting wet in the process.
Accordingly, it is an object of the present invention to provide a modular aquarium filter comprising one or more filter cartridges that may easily be connected together to form a modular filter and which may be readily disconnected to change the filter media.
It is a further object of the present invention to provide a modular aquarium filter where cartridges for biological, chemical and mechanical filters may be linked in series for ease of access and exchange.
It is still further object of the present invention to provide a filter cartridge which includes a helical flow element which improves filtering efficiency by causing the water to flow in a centrifugal fashion.
It is still further object of the present invention to provide self-sealing valving at both the inlet and outlet of the filter to expedite exchange of the cartridges without the hobbyist getting wet.